4-(Dimethylamino)pyridine as a catalyst for the lactonization of 4-hydroxy-2-methylenebutanoate esters
作者:Daniel R. Nicponski
DOI:10.1016/j.tetlet.2014.02.024
日期:2014.3
The catalytic action of 4-(dimethylamino)pyridine (DMAP) in lactonizing 4-hydroxy-2-methylenebutanoate esters to 2-methylene-γ-butyrolactones is described. The use of DMAP, which functions as an excellent complement to the more traditional acid-catalyzed lactonization protocol, allows for the synthesis of 2-methylene-γ-butyrolactones containing acid-sensitive groups under essentially neutral conditions
Die α‐Methylen‐γ‐butyrolactone 1‐28 wurden auf molluskizide Wirkung gegen Biomphalaria glabrata untersucht. Die racem. Verbindung 25 ist am wirksamsten. Die Synthese erfolgte durch modifizierte Reformatzky‐Reaktion aus den entspr. Carbonylverbindungen und Brommethylacrylsäureethylester. 7‐10, 17 und 22‐27 wurden erstmalig synthetisiert.
The electroreduction of a catalytic amount of ZnBr2 in acetonitrile provided a active Zn*, able to catalyze the reductive coupling of allyl bromides and chlorides with carbonyl compounds with high regioselectivity. Substituted α-methylene γ-lactones were obtained from functionalized allyl derivatives.
DIANION OF<i>N</i>-(<i>o</i>-METHOXYPHENYL)-2-METHYLPROPENAMIDE: A NEW REAGENT FOR THE CONVENIENT SYNTHESIS OF α-METHYLENE-γ-BUTYROLACTONES FROM CARBONYL COMPOUNDS
Dianion of N-(o-methoxyphenyl)-2-methylpropenamide was successfully generated on treatment of the amide with t-BuOK–BuLi at −78°C in THF and utilized as the key reagent for the synthesis of γ-substituted α-methylene-γ-butyrolactones.
作者:Gerald Haaima、Mary-Jeanne Lynch、Anne Routledge、Rex T. Weavers
DOI:10.1016/s0040-4020(01)87132-5
日期:1991.1
The iodoalkylidene lactones formed by reaction of alkenes with acetylenic acids in the presence of N-iodosuccinimide and subsequent free radical cyclisation, can be de-iodinated photochemically or alkylated with lithiumdiorganocuprate reagents to yield a variety of α-alkylidene lactones.